Apparatus for producing soft serve dairy products, in particular yogurt

Abstract

An apparatus for producing soft serve dairy products, especially yogurt, and comprising a freeze barrel having an inlet spaced about one-fourth of the barrel length from a rear end wall of the freeze barrel, and a beater shaft assembly which includes a square shaft, at least four blade elements mounted on the four faces of the square shaft, respectively, and four pairs of spaced pins projecting a successively radially from the four faces of the square shaft for supporting the four blade elements, respectively, on the shaft and arranged along the shaft with a first pin of the first pair of pins being located about halfway between the rear end wall of the barrel and the barrel inlet and with a first pin of each successive pair of pins except the second pair of pins being spaced slightly beyond a second pin of a preceding pair of pins in a direction toward the front end wall of the freeze barrel.

What is claimed is: 
     
       1. An apparatus for producing soft-serve dairy products, especially yogurt, said apparatus comprising a housing; a freeze barrel mounted in said housing and including a front end, a rear end having a rear end wall, and an inlet spaced about one-fourth of the length of said freeze barrel from said rear end wall and through which product mix is fed into said freeze barrel; a front plate assembly mounted over said front end of said freeze barrel for dispensing soft frozen product made in said freeze barrel; a beater shaft assembly supported in said freeze barrel for agitating and mixing the product mix and for propelling the product from said inlet to said front end of said freeze barrel; and a drive assembly for driving said beater shaft assembly, said beater shaft assembly including a shaft having a square cross-section and a longitudinal axis, four pairs of spaced pins projecting successively radially from four faces of said shaft, respectively, and extending along said shaft in a form of a spiral, and four blade elements supported on said four pairs of pins, respectively, with each blade element having a unidirectional spirally-curved longitudinal outer surface, said pairs of pins being arranged along said shaft with a first pin of a first pair of pins being spaced from said rear end wall about half-distance between said rear end wall and said inlet and with a first pin of third and fourth pairs of pins being spaced beyond a second pin of a preceding pair of pins in a direction of propelling of the product mix, each of said blade elements having a base and a fin projecting from said base and defining said unidirectional spirally-curved outer surface, said base having a substantially rectangular shape defining longitudinal and transverse edges of said base, and two spaced openings for engaging a respective pair of pins, said transverse edges being spaced from respective axes of said openings a distance substantially equal to a diameter of a pin, said fin having opposite outer edges that lie in planes that pass through respective end faces of said base and that extend slightly beyond respective longitudinal edges of said base so that when said four blade elements are mounted on said four pairs of pins, the unidirectional spirally-curved outer surfaces of the second and subsequent blade elements forming almost a perfect continuous spiral formation about said shaft. 
     
     
       2. An apparatus as set forth in claim 1 wherein a distance between axes of a second pin of the second pair of pins and a first pin of a third pair of pins and a distance between axes of a second pin of the third pair of pins and a first pin of a fourth pair of pins is equal approximately to two pin diameters. 
     
     
       3. An apparatus as set forth in claim 1 wherein said beater shaft assembly further includes four leaf springs and said base has a flat bottom surface, each of said four leaf springs being mounted between the bottom surface of the base of a respective blade element and a respective face of said shaft. 
     
     
       4. An apparatus as set forth in claim 1 wherein said fin of said blade element has opposite end faces defining said opposite outer edges, said end faces being symmetrical. 
     
     
       5. An apparatus for producing soft serve dairy products, especially yogurt, said apparatus comprising a housing, a freeze barrel mounted in said housing and including a front end, a rear end having a rear end wall; a front plate assembly mounted over said front end of said freeze barrel; a beater shaft assembly supported in said freeze barrel and including a shaft having a square cross-section, a longitudinal axis, front and rear end surfaces, and a stub portion projecting from said rear end surface of said shaft; and a drive assembly for driving said beater shaft assembly and having an output shaft connectible with said stub portion of said shaft; said beater shaft assembly further including a plurality of separate interchangeable spirally curved blade elements having opposite ends, said plurality of blade elements comprising first, second, third and fourth blade elements progressively mounted on respective four sides of said square shaft with opposite end portions of two adjacent blade elements extending a distance substantially equal to two lengths of a blade element and with an end surface of the first blade element being spaced a distance from said one of said rear end surface of said square shaft, and a fifth blade element mounted substantially symmetrically relative to the longitudinal axis of said square shaft with respect to said first blade element.